Modified naphthalene formaldehyde resin, tricyclodecane skeleton-containing naphthol compound and ester compound

ABSTRACT

A modified dimethylnaphthalene formaldehyde resin obtained by modifying a polyfunctional dimethylnaphthalene formaldehyde resin having a constituent unit represented by the following general formula [1] in a molecule thereof with at least one member selected from the group consisting of a phenol represented by the following general formula [2], a naphthol represented by the following general formula [3] and a naphthol represented by the following general formula [4], provided that at least any of the naphthol represented by the general formula [3] or the naphthol represented by the general formula [4] must be included 
                         
This resin is excellent in heat resistance and useful for thermosetting resins.

TECHNICAL FIELD

The present invention relates to a modified naphthalene formaldehyderesin. Also, the present invention relates to a tricyclodecaneskeleton-containing naphthol compound which is used for the productionof the modified naphthalene formaldehyde resin and to an ester compoundserving as a raw material thereof.

BACKGROUND ART

Modified naphthalene formaldehyde resins can be used for widespreadapplications such as an electrical insulating material, a resin forresist, a semiconductor sealing resin, an adhesive for printed wiringboard, a matrix resin for electrical laminate or prepreg to be mountedin electrical instruments, electronic instruments, industrialinstruments, etc., a buildup laminate material, a resin forfiber-reinforced plastic, a sealing resin for liquid crystal displaypanel, a paint, a variety of coating agents, an adhesive and the like.

An aromatic hydrocarbon resin obtained by allowing a polycyclic aromatichydrocarbon composed mainly of a monomethylnaphthalene and/or adimethylnaphthalene and paraformaldehyde to react with each other in thepresence of an aromatic monosulfonic acid is known, and the obtainedresin is excellent in compatibility with a liquid epoxy resin andsolubility in xylene (see Patent Document 1).

Also, there is known a method for obtaining a phenol resin having astructure in which naphthalene and a phenolic hydroxyl group-containingcompound are bonded via a methylene group through a reaction between amethoxymethylene naphthalene compound and a phenolic hydroxylgroup-containing compound such as phenol, cresol, naphthol, etc. in thepresence of diethyl sulfate (see Patent Document 2).

Now, in order to use a resin obtained through a condensation reaction ofa polycyclic aromatic hydrocarbon formaldehyde resin and a phenolichydroxyl group-containing compound for a thermosetting resinapplication, it is more preferable that the obtained resin ispolyfunctional.

However, in the case where naphthalene or a monomethylnaphthalene isused as a raw material of resin, it is difficult to obtain apolyfunctional resin by a usual method so that it was necessary toperform a special reaction such as an interface reaction (see PatentDocuments 2 and 3).

[Patent Document 1] JP-A-54-86593

[Patent Document 2] JP-A-2004-91550

[Patent Document 3] JP-A-61-228013

[Patent Document 4] JP-A-11-92543

DISCLOSURE OF THE INVENTION Problems that the Invention is to Solve

Furthermore, according to investigations made by the present inventors,in addition to naphthalene and a monomethylnaphthalene, even when adimethylnaphthalene is used as a raw material, there may be the casewhere a polyfunctional resin is not obtained, and it has become clearthat in order to obtain a polyfunctional resin serving as a rawmaterial, selection of the kind of the dimethylnaphthalene is important.

An object of the present invention is to provide a modifieddimethylnaphthalene formaldehyde resin with high heat resistance whichis useful for a thermosetting resin application, the modifieddimethylnaphthalene formaldehyde resin being obtained by using, as a rawmaterial, a dimethylnaphthalene formaldehyde resin which ispolyfunctional and rich in reactivity and modifying thedimethylnaphthalene formaldehyde resin with a naphthol or a naphthol anda phenol. Furthermore, another object of the present invention is toprovide a tricyclodecane skeleton-containing naphthol compound capableof being used for the modification of a dimethylnaphthalene formaldehyderesin and an ester compound serving as a raw material thereof.

Means for Solving the Problems

The present inventors made extensive and intensive investigations. As aresult, it has been found that the foregoing objects can be attained byobtaining a modified dimethylnaphthalene formaldehyde resin using apolyfunctional dimethylnaphthalene formaldehyde resin which is obtainedby using a dimethylnaphthalene having one methyl group on each of twobenzene rings in a naphthalene ring thereof and allowing this to reactwith formaldehyde, leading to the present invention.

That is, the present invention is concerned with:

(1) A modified dimethylnaphthalene formaldehyde resin obtained bymodifying a polyfunctional dimethylnaphthalene formaldehyde resin havinga constituent unit represented by the following general formula [1] in amolecule thereof with at least one member selected from the groupconsisting of a phenol represented by the following general formula [2],a naphthol represented by the following general formula [3] and anaphthol represented by the following general formula [4] (provided thatat least any of the naphthol represented by the general formula [3] orthe naphthol represented by the general formula [4] is included):

wherein

R¹ represents an alkyl group having from 1 to 4 carbon atoms; each ofR², R³ and R⁴ independently represents a hydrogen atom or an alkyl grouphaving from 1 to 3 carbon atoms; A is represented by —(OCH₂)_(t)—; t isfrom 0 to 2; x is from 0 to 4; and y represents an integer of from 0 to2;

(2) The modified dimethylnaphthalene formaldehyde resin as set forthabove in (1), wherein in the polyfunctional dimethylnaphthaleneformaldehyde resin having a constituent unit represented by the generalformula [1] in a molecule thereof, a mean value of the number ofhydrogen atoms substituted by a reaction for producing thedimethylnaphthalene formaldehyde resin among the six hydrogen atomsdirectly bonded on the naphthalene ring is from 1.5 to 3.5;

(3) The modified dimethylnaphthalene formaldehyde resin as set forthabove in (1) or (2), wherein a dimethylnaphthalene which is a rawmaterial of the polyfunctional dimethylnaphthalene formaldehyde resinhaving a constituent unit represented by the general formula [1] in amolecule thereof is at least one member selected from the groupconsisting of 1,5-dimethylnaphthalene, 1,6-dimethylnaphthalene,2,6-dimethylnaphthalene, 1,7-dimethylnaphthalene,1,8-dimethylnaphthalene and 2,7-dimethylnaphthalene;

(4) The modified dimethylnaphthalene formaldehyde resin as set forthabove in (3), wherein the dimethylnaphthalene is a dimethylnaphthaleneobtained through a chemical synthesis using, as starting raw materials,o-xylene and 1,3-butadiene, or p-xylene and 1,3-butadiene;

(5) The modified dimethylnaphthalene formaldehyde resin as set forthabove in any one of (1) to (4), wherein the phenol represented by thegeneral formula [2] is at least one member selected from the groupconsisting of phenol, cresol, 4-t-butylphenol and xylenol;

(6) The modified dimethylnaphthalene formaldehyde resin as set forthabove in any one of (1) to (5), wherein the naphthol represented by thegeneral formula [3] is 1-naphthol and/or 2-naphthol;

(7) The modified dimethylnaphthalene formaldehyde resin as set forthabove in any one of (1) to (6), wherein the naphthol represented by thegeneral formula [4] is the following compound:

(8) The modified dimethylnaphthalene formaldehyde resin as set forthabove in any one of (1) to (7), having a weight average molecular weight(Mw) of from 500 to 5,000;

(9) A method for producing a tricyclodecane skeleton-containing naphtholcompound represented by the following formula (1):

including a step of subjecting an ester compound represented by thefollowing formula (2):

to a Fries rearrangement reaction;

(10) A tricyclodecane skeleton-containing naphthol compound representedby the following formula (1):

(11) A method for producing an ester compound represented by thefollowing formula (2):

including a step of allowing tricyclo[5.2.1.0^(2,6)]deca-3-ene andcarbon monoxide to react with each other in the presence of hydrogenfluoride at from 20 to 40° C. to obtain an acyl fluoride represented bythe following formula (3):

and subjecting the obtained acyl fluoride to an esterification reactionwith 1-naphthol at not higher than 20° C.; and

(12) An ester compound represented by the following formula (2):

Advantages of the Invention

The modified dimethylnaphthalene formaldehyde resin of the presentinvention is excellent in heat resistance and useful for thermosettingresins which are used for an electrical insulating material, a resin forresist, a semiconductor sealing resin, an adhesive for printed wiringboard, a matrix resin for electrical laminate or prepreg to be mountedin electrical instruments, electronic instruments, industrialinstruments, etc., a buildup laminate material, a resin forfiber-reinforced plastic, a sealing resin for liquid crystal displaypanel, a paint, a variety of coating agents, an adhesive, a laminate forelectrical or electronic parts, a molded article, a coating material, asealing material and the like. Also, the tricyclodecaneskeleton-containing naphthol compound represented by the foregoingformula (1) is useful as a variety of industrial chemical raw materialsand a variety of raw materials for producing an optical functionalmaterial or an electronic functional material.

Best Modes for Carrying Out the Invention

As described previously, the present invention is concerned with amodified dimethylnaphthalene formaldehyde resin (hereinafter sometimesabbreviated as “modified resin”) which is obtained by modifying apolyfunctional dimethylnaphthalene formaldehyde resin having aconstituent unit represented by the following general formula [1] in amolecule thereof:

with at least one member selected from the group consisting of a phenolrepresented by the following general formula [2], a naphthol representedby the following general formula [3] and a naphthol represented by thefollowing general formula [4]:

provided that

at least any of the naphthol represented by the general formula [3] orthe naphthol represented by the general formula [4] is included.

Here, the “polyfunctionality” of the polyfunctional dimethylnaphthaleneformaldehyde resin as referred to in the present specification meansthat a mean value of the number of hydrogen atoms substituted by areaction for producing a dimethylnaphthalene formaldehyde resin amongthe six hydrogen atoms directly bonded on the naphthalene ring in thedimethylnaphthalene (hereinafter sometimes referred to as “mean value ofthe number of substituted hydrogen atoms per one naphthalene ring in thedimethylnaphthalene formaldehyde resin”) exceeds 1.5. In measuring theobtained resin by means of ¹H-NMR, the number of substituted hydrogenatoms is a numerical value calculated utilizing an integrated value ofmethyl protons in the vicinity of from 2.3 to 3.2 ppm and an integratedvalue of protons directly bonded on the aromatic ring in the vicinity offrom 6.8 to 8.2 ppm.

<Polyfunctional Dimethylnaphthalene Formaldehyde Resin>

The polyfunctional dimethylnaphthalene formaldehyde resin is obtainedthrough a condensation reaction between a dimethylnaphthalene having onemethyl group on each of two benzene rings in a naphthalene ring thereofand formaldehyde.

(Dimethylnaphthalene)

The dimethylnaphthalene as a raw material of the polyfunctionaldimethylnaphthalene formaldehyde resin is obtained through a chemicalsynthesis using, as starting raw materials, o-xylene and 1,3-butadiene,or p-xylene and 1,3-butadiene. Specifically, the dimethylnaphthalenewhich is used in the present invention is at least one member selectedfrom the group consisting of 1,5-dimethylnaphthalene,1,6-dimethylnaphthalene, 2,6-dimethylnaphthalene,1,7-dimethylnaphthalene, 1,8-dimethylnaphthalene and2,7-dimethylnaphthalene.

The dimethylnaphthalene of at least one member selected from the groupconsisting of 1,5-dimethylnaphthalene, 1,6-dimethylnaphthalene and2,6-dimethylnaphthalene can be obtained by allowing o-xylene and1,3-butadiene to react with each other in the presence of a strongalkali catalyst to form o-toluoyl-1-pentene (step A), subsequentlycyclizing the o-toluoyl-1-pentene to obtain a tetralin compound (step B)and dehydrogenating the tetralin compound to obtain a naphthalenecompound (step C) and optionally, isomerizing the naphthalene compoundto obtain a structural isomer (step D), followed by separation andpurification by means of distillation, crystallization or the like, ifnecessary.

Also, the dimethylnaphthalene of at least one member selected from thegroup consisting of 1,7-dimethylnaphthalene, 1,8-dimethylnaphthalene and2,7-dimethylnaphthalene can be obtained by allowing p-xylene and1,3-butadiene as starting raw materials to react with each otheraccording to the foregoing steps A to C and optionally, the step D,followed by separation and purification by means of distillation,crystallization or the like, if necessary.

As the foregoing steps A to D, known methods, for example, a methoddisclosed in JP-A-2006-70000 can be utilized.

In this way, by producing the dimethylnaphthalene formaldehyde resinusing the dimethylnaphthalene obtained through a chemical synthesisusing a xylene (o-xylene or p-xylene) and 1,3-butadiene as starting rawmaterials in a process including the foregoing steps A to C andoptionally, the step D, it is possible to obtain a polyfunctionaldimethylnaphthalene formaldehyde resin which is polyfunctional and richin reactivity and in which a content of each of a sulfur atom and anitrogen atom in the resin is not more than 0.5 ppm.

It is important that the raw material dimethylnaphthalene which is usedin the present invention is a dimethylnaphthalene having one methylgroup on each of two benzene rings in a naphthalene ring thereof. As aresult of extensive and intensive investigations made by the presentinventors, it has become clear that in the case of using, as a rawmaterial, an unsubstituted compound; a monomethylnaphthalene such as1-methylnaphthalene, etc.; and at least one dimethylnaphthalene selectedfrom the group consisting of 1,2-dimethylnaphthalene,1,3-dimethylnaphthalene, 1,4-dimethylnaphthalene and2,3-dimethylnaphthalene each having two methyl groups substituted onlyon a benzene ring of one side of a naphthalene ring thereof, apolyfunctional naphthalene formaldehyde resin is not obtainable unless aspecial reaction mode such as an interface reaction is adopted. Also, inthe case of using a naphthalene compound having three or more methylgroups substituted thereon, the number of reactive points withformaldehyde (the number of hydrogen atoms directly bonded on thenaphthalene ring) becomes small so that a polyfunctional naphthaleneformaldehyde resin could not be obtained.

The mean value of the number of substituted hydrogen atoms per onenaphthalene ring in the polyfunctional dimethylnaphthalene formaldehyderesin is from 1.5 to 3.5, preferably from 1.8 to 3.5, more preferablyfrom 2.0 to 3.5, further preferably from 2.0 to 3.3, and especiallypreferably from 2.5 to 3.0. What the mean value of the number ofsubstituted hydrogen atoms per one naphthalene ring in the resin is lessthan 1.5 is not preferable because an active group (for example, amethylol group, a methoxymethyl group, etc.) which is rich in reactivitywith a third component becomes few so that there is a concern that anacquisition amount of a modified resin obtained by a reaction with thethird component is small. In particular, what the mean value of thenumber of substituted hydrogen atoms is 2.0 or more is preferablebecause the reactivity with the third component is sufficient. On theother hand, what the mean value of the number of substituted hydrogenatoms per one naphthalene ring in the resin exceeds 3.5 is technicallydifficult.

Since the polyfunctional dimethylnaphthalene formaldehyde resin has highreactivity with a phenol, a carboxylic acid, a polyol, etc. each havingactive hydrogen.

(Formaldehyde)

As the formaldehyde, compounds capable of generating formaldehyde, suchas formalin, paraformaldehyde, trioxan, etc., all of which areindustrially easily available, and the like can be exemplified. Inperforming a condensation reaction, a molar ratio of thedimethylnaphthalene to formaldehyde is from 1/1 to 1/6, preferably from1/1.5 to 1/6, more preferably 1/2 to 1/6, further preferably from 1/2.5to 1/6, and especially preferably from 1/2.5 to 1/5. When the molarratio of the dimethylnaphthalene to formaldehyde is made to fall withinthe foregoing range, not only a resin yield of the obtaineddimethylnaphthalene formaldehyde resin can be kept relatively high, butan amount of unreacted residual formaldehyde can be made small.

(Production Method of Polyfunctional Dimethylnaphthalene FormaldehydeResin)

The condensation reaction of the foregoing dimethylnaphthalene compoundand the foregoing formaldehyde is carried out in the presence of waterand an acid catalyst.

As the acid catalyst, sulfuric acid, p-toluenesulfonic acid and the likeare exemplified, but in general, sulfuric acid is suitable. For example,in the case of using sulfuric acid, a use amount of the acid catalyst isadjusted such that a concentration of sulfuric acid in a componentcomposed of formaldehyde, water and sulfuric acid is preferably from 20to 55% by mass, and more preferably from 25 to 40% by mass. When theconcentration of sulfuric acid is made to fall within this range, anappropriate reaction rate is obtainable, and furthermore, it is possibleto prevent an increase of the viscosity of the resin to be caused due toa fast reaction rate. On the other hand, in the case of usingp-toluenesulfonic acid, it is preferable to use p-toluenesulfonic acidso as to adjust its concentration slightly higher than that in the caseof using sulfuric acid, for example, a concentration of paraformaldehydein a component composed of formaldehyde, water and paraformaldehyde isadjusted at from 35 to 60% by mass.

Also, a concentration of formaldehyde in a component composed offormaldehyde, water and sulfuric acid in the raw material components ispreferably from 20 to 40% by mass. By setting the concentration offormaldehyde to be from 20 to 40% by mass, a reaction rate which ispreferable for practical use is obtainable.

The condensation reaction of the naphthalene compound and formaldehydeis usually carried out at atmospheric pressure and carried out whilerefluxing upon heating at 100° C. as a boiling point of water. However,a reaction temperature may be properly chosen within the range of fromordinary temperature to 100° C., and a reaction pressure may be anelevated pressure of from about 0.001 to 0.02 MPa (gauge pressure). Inthe case of using, as a raw material, a dimethylnaphthalene having amelting point of 100° C. or higher, for the purpose of setting thereaction temperature to be its melting point or higher, it is preferablethat the reaction is carried out under an elevated pressure of fromabout 0.01 to 0.02 MPa (gauge pressure). Also, if desired, a solventwhich is inert to the condensation reaction can be used. Examples of thesolvent include an aromatic hydrocarbon such as ethylbenzene, etc.; asaturated aliphatic hydrocarbon such as heptane, hexane, etc.; analicyclic hydrocarbon such as cyclohexane, etc.; a ketone such as methylisobutyl ketone, etc.; an ether such as dioxane, dibutyl ether, etc.; analcohol such as 2-propanol, etc.; a carboxylic acid ester such as ethylpropionate, etc.; a carboxylic acid such as acetic acid, etc.; and thelike.

In general, a reaction time is preferably from about 4 to 10 hours, andmore preferably from 5 to 8 hours. By adopting such a reaction time, thedimethylnaphthalene formaldehyde resin having desired properties isobtainable economically and industrially advantageously.

Also, if desired, the present condensation reaction may be carried outwhile heat refluxing by the addition of an aliphatic lower alcohol suchas methanol, ethanol, isopropanol, etc. By performing the reaction bythe addition of an aliphatic lower alcohol, the aliphatic lower alcoholis captured as a terminal group of the dimethylnaphthalene formaldehyderesin, namely a methylol group directly bonded on the naphthalene ringof the repeating unit structure is partially captured as an alkoxygroup, thereby enabling one to realize a low molecular weight and todecrease the viscosity.

After the condensation reaction, if desired, by after further adding theforegoing solvent for dilution, allowing the mixture to stand to causetwo-phase separation, separating a resin phase as an oily phase from anaqueous phase, further washing it with water, thereby completelyremoving the acid catalyst and then removing the added solvent and theunreacted raw material dimethylnaphthalene by a general method such asdistillation, etc., a polyfunctional dimethylnaphthalene formaldehyderesin having desired properties is obtainable.

(Characteristic Values of Polyfunctional DimethylnaphthaleneFormaldehyde Resin)

A weight average molecular weight (Mw) of the thus obtainedpolyfunctional dimethylnaphthalene formaldehyde resin is preferably from300 to 1,500, more preferably from 500 to 1,300, and further preferablyfrom 800 to 1,200; and a degree of dispersion (Mw/Mn) is preferably from1.5 to 3, and more preferably from 1.5 to 2.3. Also, each of a contentof a sulfur atom and a content of a nitrogen atom in the polyfunctionaldimethylnaphthalene formaldehyde resin is not more than 0.5 ppm.

Also, it is possible to modify the thus obtained polyfunctionaldimethylnaphthalene formaldehyde resin with a naphthol or the like inthe following manners.

In the general formula [1], A is represented by —(OCH₂)_(t)—; and t isfrom 0 to 2. Also, x is from 0 to 4, preferably from 0 to 2, and morepreferably from 0 to 1.

<Modified Dimethylnaphthalene Formaldehyde Resin>

The modified dimethylnaphthalene formaldehyde resin having been modifiedwith a naphthol, or a naphthol and a phenol according to the presentinvention is obtained by adding the foregoing naphthol having a phenolichydroxyl group and optionally the foregoing phenol to the foregoingpolyfunctional dimethylnaphthalene formaldehyde resin and subjecting themixture to a condensation reaction upon heating in the presence of anacid catalyst. The naphthol is represented by the foregoing generalformula [3] or [4]; and the phenol is represented by the foregoinggeneral formula [2].

In the foregoing general formula [3], each of R² and R³ independentlyrepresents a hydrogen atom or an alkyl group having from 1 to 3 carbonatoms. Examples of the alkyl group include a methyl group, an ethylgroup, an n-propyl group and an isopropyl group. Each of R² and R³ ispreferably a hydrogen atom.

In the foregoing general formula [4], R⁴ represents a hydrogen atom oran alkyl group having from 1 to 3 carbon atoms.

Examples of the alkyl group include a methyl group, an ethyl group, ann-propyl group and an isopropyl group. R⁴ is preferably a hydrogen atom.

The naphthol is preferably 1-naphthol, 2-naphthol or a tricyclodecaneskeleton-containing naphthol compound represented by the followingformula (1) or (4), and from the viewpoint of heat resistance, atricyclodecane skeleton-containing naphthol compound represented by theformula (1) is more preferable. The naphthol may be used singly or incombinations with two or more kinds thereof.

In modifying the polyfunctional dimethylnaphthalene formaldehyde resin,from the viewpoint of heat resistance, the use of the naphthol isessential. In any of the naphthol represented by the foregoing generalformula [3] and the naphthol represented by the foregoing generalformula [4], a use amount of the naphthol is preferably from 10 to 150parts by mass, more preferably from 20 to 120 parts by mass, and furtherpreferably from 30 to 100 parts by mass, and from the viewpoint of heatresistance, especially preferably from 40 to 90 parts by mass based on100 parts of the polyfunctional dimethylnaphthalene formaldehyde resin.Also, in the case of jointly using the naphthol represented by theforegoing general formula [3] and the naphthol represented by theforegoing general formula [4], a total use amount thereof is preferablyfrom 10 to 150 parts by mass, more preferably from 20 to 120 parts bymass, and further preferably from 30 to 100 parts by mass, and from theviewpoint of heat resistance, especially preferably from 40 to 90 partsby mass based on 100 parts by mass of the polyfunctionaldimethylnaphthalene formaldehyde resin.

Also, in the foregoing general formula [2], R¹ represents an alkyl grouphaving from 1 to 4 carbon atoms. Examples of the alkyl group include amethyl group, an ethyl group, an n-propyl group, an isopropyl group, ann-butyl group, an isobutyl group, an s-butyl group and a t-butyl group.

y is from 0 to 2, and preferably 0 or 1.

It is preferable to use at least one member selected from the groupconsisting of phenol, cresol, 4-t-butylphenol, xylenol andpropionylphenol as the phenol.

In modifying the polyfunctional dimethylnaphthalene formaldehyde resin,if desired, the heat resistance can also be adjusted by using the phenolalong with the naphthol. In that case, a use amount of the phenol ispreferably not more than 80 parts by mass, more preferably not more than40 parts by mass, and further preferably not more than 10 parts by massbased on 100 parts by mass of the polyfunctional dimethylnaphthaleneformaldehyde resin, and for the purpose of enhancing the heat resistanceof the modified resin, it is especially preferable that the phenol isnot used.

The condensation reaction of the polyfunctional dimethylnaphthaleneformaldehyde resin and the foregoing naphthol and the foregoing phenolis generally carried out at atmospheric pressure and carried out whilerefluxing upon heating at a melting point of each of the polyfunctionaldimethylnaphthalene formaldehyde resin, the naphthol and the phenol orhigher (usually from 130 to 250° C.). Also, if desired, the condensationreaction can be carried out under an elevated pressure. Furthermore, ifdesired, a solvent which is inert to the condensation reaction can beused. Examples of the solvent include an aromatic hydrocarbon such asethylbenzene, etc.; a saturated aliphatic hydrocarbon such as heptane,hexane, etc.; an alicyclic hydrocarbon such as cyclohexane, etc.; aketone such as methyl isobutyl ketone, etc.; an ether such as dioxane,dibutyl ether, etc.; an alcohol such as 2-propanol, etc.; a carboxylicacid ester such as ethyl propionate, etc.; a carboxylic acid such asacetic acid, etc.; and the like.

Examples of the acid catalyst which can be used for the condensationreaction include sulfuric acid, p-toluenesulfonic acid, etc. Of these,p-toluenesulfonic acid is preferable. In the case of usingp-toluenesulfonic acid, a use amount of the acid catalyst is adjustedsuch that a concentration of p-toluenesulfonic acid in a componentcomposed of the polyfunctional dimethylnaphthalene aldehyde resin, thenaphthol and p-toluenesulfonic acid is preferably from 0.0001 to 0.5% bymass, more preferably from 0.01 to 0.5 by mass, and further preferablyfrom 0.05 to 0.4% by mass. When the concentration of p-toluenesulfonicacid is made to fall within the foregoing range, an appropriate reactionrate is obtainable, and it is possible to prevent an increase of theviscosity of the resin to be caused due to a large reaction rate.

A reaction time is preferably from about 1 to 10 hours, and morepreferably from about 2 to 6 hours. When the reaction time falls withinthis range, a modified resin having desired properties is obtainableeconomically and industrially advantageously.

After completion of the reaction, if desired, by after further addingthe foregoing solvent for dilution, allowing the mixture to stand tocause two-phase separation, separating a resin phase as an oily phasefrom an aqueous phase, further washing the resin phase with water,thereby completely removing the acid catalyst and then removing theadded solvent and the unreacted naphthol by a general method such asdistillation, etc., a modified resin is obtainable.

(Characteristic Values of Modified Resin)

Though a hydroxyl group value (mg-KOH/g) of the thus obtained modifiedresin of the present invention is not particularly limited, it ispreferably from 10 to 500, more preferably from 10 to 400, and furtherpreferably from 10 to 300.

Also, though a weight average molecular weight (Mw) of the thus obtainedmodified resin of the present invention is not particularly limited, itis preferably from 500 to 5,000, more preferably from 1,000 to 5,000,and further preferably from 1,500 to 5,000; and a degree of dispersion(Mw/Mn) is preferably from 1.5 to 6, more preferably from 1.5 to 5, andfurther preferably from 1.8 to 3.5.

<Production Method of Naphthol>

A production method of the naphthol represented by the general formula[4] is hereunder described.

For the sake of convenience, though an example of a production method ofa tricyclodecane skeleton-containing naphthol compound represented bythe following formula (1):

(hereinafter abbreviated as “naphthol compound (1)”) is exemplified,other naphthol compounds in which the position of the substituent isdifferent can be produced in the same method.

The foregoing naphthol compound (1) can be produced through thefollowing three stages.

(First Stage)

Production of acyl fluoride represented by the following formula (3):

(hereinafter referred to as “acyl fluoride (3)”) by means of acarbonylation reaction of tricyclo[5.2.1.0^(2,6)]deca-3-ene (hereinafterabbreviated as “DHDCPD”)(Second Stage)

Production of an ester compound represented by the following formula(2):

(hereinafter referred to as “ester compound (2)”) by means of anesterification reaction between the foregoing acyl fluoride (3) and1-naphthol(Third Stage)

Production of the naphthol compound (1) by means of the Friesrearrangement of the foregoing ester compound (2)

(First Stage: Production of the Acyl Fluoride (3))

A carbonylation reaction solution containing the acyl fluoride (3) isobtained by allowing DHDCPD to react in the presence of hydrogenfluoride (hereinafter abbreviated as “HF”) under an elevated pressurewith carbon monoxide. On that occasion, an inert gas such as nitrogen,methane, etc. may be contained in carbon monoxide.

Though a partial pressure of carbon monoxide is not particularlylimited, in general, it is from about 0.5 to 5 MPa, and more preferablyfrom 1 to 3 MPa. When the partial pressure of carbon monoxide fallswithin the foregoing range, the carbonylation reaction is sufficientlyadvanced, a side reaction such as disproportionation, polymerization,etc. is suppressed, and large expenditure on plant and equipment is notrequired. Also, a reaction temperature is usually from 10 to 60° C., andfrom the viewpoint of yield, it is preferably from 20 to 40° C., andmore preferably from 25 to 35° C. The highest yield is obtained in thevicinity of 30° C.

HF is preferably a substantially anhydrous material.

From the viewpoint that not only the carbonylation reaction issufficiently advanced, but a side reaction such as disproportionation,polymerization, etc. is suppressed and also from the viewpoints ofexpenses for separating HF, volume efficiency of a reaction apparatusand the like, a use amount of HF is preferably from 1 to 30 molar times,more preferably from 4 to 12 molar times, and further preferably from 6to 10 molar times relative to the DHDCPD.

(Second Stage: Production of the Ester Compound (2))

Though after removing HF from the carbonylation reaction solutioncontaining the acyl fluoride (3) obtained in the first stage, theresidue may be allowed to react with 1-naphtol, HF acts as a catalyst inthe esterification reaction, and therefore, it is preferable that thecarbonylation reaction solution is mixed with 1-naphthol as it iswithout separating HF therefrom and allowed to react with each other,thereby obtaining an esterification reaction solution containing theester compound (2).

A reaction temperature is not higher than 20° C., and from theviewpoints of suppressing decomposition of the formed ester, suppressingby-production of water due to a dehydration reaction of the addedalcohol and the like, the reaction temperature is preferably from −40 to20° C., more preferably from −20 to 10° C., and further preferably from−10 to 10° C. Though there may be the case where the Fries rearrangementof the third stage as described later is advanced depending upon thereaction temperature, there is not particularly caused a problem.

As a standard, a use amount of 1-naphthol is preferably from 0.1 to 3molar times, more preferably from 0.3 to 2 molar times, and furtherpreferably from 0.3 to 0.8 molar times relative to the DHDCPD used inthe first stage.

(Third Stage: Tricyclodecane Skeleton-Containing Naphthol Compound)

By elevating a temperature of the esterification reaction solutioncontaining the ester compound (2) obtained in the second stage, theFries rearrangement of the ester compound (2) is advanced, therebyforming the naphthol compound (1). In this rearrangement reaction, HFacts as a catalyst, too.

A reaction temperature is preferably from −10 to 40° C., more preferablyfrom −10 to 30° C., further preferably from −10 to 25° C., andespecially preferably from −10 to 20° C.; and it is preferable to keepthe temperature for from 6 to 40 hours. However, since an equilibriumcomposition is present between the Fries rearrangement compound and theester compound (2), after a proportion of the Fries rearrangementcompound is increased while keeping the reaction system at a temperaturein the vicinity of 20° C. for from 1 to 3 hours, the reaction system iscooled to about 0° C. and kept for from 8 to 10 hours, whereby theproportion of the naphthol compound (1) as the Fries rearrangementcompound can be further increased.

The reaction mode of the foregoing first to third stages is notparticularly limited, and it may be any of a semi-continuous mode or acontinuous mode or the like.

In any of the reactions of the first to third stages, a solvent whichhas ability to dissolve DHDCPD as a raw material therein and which isinert to DHDCPD and HF, for example, a saturated aliphatic hydrocarbonsuch as hexane, heptane, decane, etc., or the like may be used. In thecase of using a solvent, the polymerization reaction is easilysuppressed, and the yield is enhanced; however, when an excessivesolvent is used, the volume efficiency of the reaction apparatus islowered, and at the same time, deterioration of a basic unit for energyrequired for the separation is caused. Therefore, the necessity of useand the use amount are properly chosen. In the case of using a solventin the first stage, its amount is preferably from 0.5 to 1 time by massrelative to the total sum of DHDCPD and HF. In the second stage, in thecase of using the solvent used in the first stage as it is, it ispreferable to add the solvent in an amount of from 0.5 to 1.5 times bymass relative to the 1-naphthol. In the third stage, when the solvent isused in the first and second stages, it is not necessary to further adda solvent.

(Treatment after Completion of the Reaction of the Third Stage)

After distilling off HF from the reaction solution containing thenaphthol compound (1) obtained through the first to third stages, bypurifying the residue by a usual method such as distillation, etc., thenaphthol compound (1) in which a proportion of the naphthol compound (1)is 80% by mole or more relative to the total sum of the ester compound(2) and the naphthol compound (1) can be obtained.

The tricyclodecane skeleton of the naphthol compound (1) includesskeleton isomers of an endo-isomer and an exo-isomer, and the naphtholcompound (1) is a mixture of those isomers. A ratio of the endo-isomerto the exo-isomer of the tricyclodecane skeleton is not particularlylimited, and at the carbonylation temperature of the first stage of 30°C., the ratio of the endo-isomer to the exo-isomer is from 0.4 to 0.6.

A production method of DHDCPD as the raw material of the first stage isnot particularly limited, and DHDCPD can be produced by means ofhydrogenation of dicyclopentadiene (hereinafter abbreviated as “DCPD”)by a known method disclosed in, for example, JP-A-2003-128593, etc.

EXAMPLES

The present invention is hereunder described in more detail withreference to the following Examples, but it should not be construed thatthe present invention is limited to these Examples.

(Mean Value of the Number of Substituted Hydrogen Atoms Per OneNaphthalene Ring)

¹H-NMR apparatus: Model JNM-AL400 (400 MHz) (manufactured by JEOL Ltd.)

Solvent: CDCl₃ (Deutero chloroform)

Internal standard material: Tetramethylsilane

Calculation method of mean value of the number of substituted hydrogenatoms:

The resin was dissolved in the foregoing solvent (deuteron chloroform),and the solution was subjected to ¹H-NMR measurement. When an integratedvalue of methyl protons of a dimethylnaphthalene structure in thevicinity of from 2.3 to 3.2 ppm was defined as 6 which is the number ofmethyl protons, an integrated value of protons directly bonded on thenaphthalene ring in the vicinity of from 6.8 to 8.2 ppm was calculated;and a value obtained by subtracting the thus calculated value from 6which is the number of hydrogen atoms directly bonded on the naphthalenering of the dimethylnaphthalene structure was defined as a mean value ofthe number of hydrogen atoms substituted by a reaction for producing apolyfunctional naphthalene formaldehyde resin among the six hydrogenatoms directly bonded on the naphthalene ring (mean value of the numberof substituted hydrogen atoms per one naphthalene ring).

<Measurement of Molecular Weight>

A weight average molecular weight (Mw) and a number average molecularweight (Mn) as reduced into polystyrene were determined by means of agel permeation chromatography (GPC) analysis, and a degree of dispersion(Mw/Mn) was determined.

—Gel Permeation Chromatography (GPC) Measurement—

Apparatus: Model Shodex GPC-101 (manufactured by Showa Denko K.K.)

Column: LF-804×3

Eluent: THF 1 mL/min

Temperature: 40° C.

<Hydroxyl Group Value>

The hydroxyl group value was determined by dissolving 2 g of a modifiedresin in 20 mL of an acetic anhydride/pyridine mixed solution (volumeratio=1/9) and allowing it to react and titrating a reaction solutionthereof with a 1 mole/L sodium hydroxide aqueous solution. A titrationend point was confirmed with phenolphthalein as an indicator. Similarly,20 mL of an acetic anhydride/pyridine mixed solution (volume ratio=1/9)as a blank sample was also titrated, and a hydroxyl group value wascalculated from a difference in titer from the blank sample according tothe following expression.

Hydroxyl group value=56.1 (mg/mL)×(Difference in titer (mL))×(Sodiumhydroxide aqueous solution factor) ÷(Modified resin amount (g))

<Heat Resistance>

Apparatus: TG/DTA6200, manufactured by SII Nano Technology Inc.

Measurement temperature: From 30 to 550° C. (temperature elevation rate:10° C./min)

At a point when the temperature reached 400° C., a mass loss rate wasmeasured and defined as an index of the heat resistance.

Synthesis Example 1

Synthesis of tricyclo[5.2.1.0^(2,6)]deca-3-ene (DHDCPD):

2,000 g of dicyclopentadiene (DCPD) (manufactured by MaruzenPetrochemical Co., Ltd., purity: 99%) was allowed to react in thepresence of a Cu—Cr hydrogenation catalyst under a hydrogen pressure of2 MPa at 90° C. for about 5 hours until the absorption of hydrogen wasnot recognized. After completion of the reaction, the Cu—Crhydrogenation catalyst was removed by means of filtration, and theresidue was then purified by means of distillation, thereby obtaining1,850 g of DHDCPD (purity: 98.5%).

Example 1

Production of Naphthol Compound (1)

(First Stage: Production of Acyl Fluoride (3))

An experiment was carried out using a stainless steel-made autoclavehaving an internal volume of 500 mL and equipped with a knuck drive typestirrer, three inlet nozzles at an upper part thereof and one drawingnozzle at a bottom thereof, in which an internal temperature could becontrolled by a jacket.

First of all, after the inside of the autoclave was purged with carbonmonoxide, 189 g (9.4 moles) of hydrogen fluoride was introducedthereinto, and a liquid temperature was controlled to 30° C., followedby elevating a pressure up to 2 MPa with carbon monoxide.

236 g of an n-heptane solution having 141.1 g (1.05 moles) of DHDCPDdissolved therein was fed from the upper part of the autoclave whilekeeping a reaction temperature at 30° C. and keeping a reaction pressureat 2 MPa, thereby achieving a carbonylation reaction. After completionof feed of DHDCPD, the stirring was continued for about 10 minutes untilabsorption of carbon monoxide was not recognized.

The formation of the acyl fluoride (3) was confirmed by the presence ofa corresponding ethyl ester. A part of the obtained reaction solutionwas sampled in cooled ethanol, to which was then added water, therebyseparating an oily phase and an aqueous phase from each other. Afterneutralizing the oily phase and washing it with water, the resultingoily phase was analyzed by means of gas chromatography. As a result, amajor product was found to be ethylexo-tricyclo[5.2.1.0^(2,6)]decane-2-carboxylate and ethylendo-tricyclo[5.2.1.0^(2,6)]decane-2-carboxylate, with anendo-isomer/exo-isomer ratio being 0.53.

(Second Stage: Production of Ester Compound (2))

Subsequently, 83.4 g (0.58 moles) of 1-naphthol and 83.4 g of n-heptanewere introduced into a stainless steel-made autoclave having an internalvolume of one liter and equipped with a knuck drive type stirrer, threeinlet nozzles at an upper part thereof and one drawing nozzle at abottom thereof, in which an internal temperature could be controlled bya jacket. After cooling to 0° C., the previously synthesized acylfluoride-containing carbonylation reaction solution was added withstirring through pipe connection, thereby achieving an esterificationreaction.

Apart of the obtained reaction solution was sampled into ice water,thereby separating an oily phase and an aqueous phase from each other.After neutralizing the oily phase and washing it with water, theresulting oily phase was analyzed by means of gas chromatography. As aresult, a total purity of the ester compound (2) and the naphtholcompound (1) as a Fries rearrangement compound (ester compound(2)/naphthol compound (1)=95.7/4.3) was found to be 75.1%

Also, a desired component was isolated by means of rectification using arectifying column (theoretical number of plates: 20 plates) and analyzedby means of GC-MS. As a result, a molecular weight of the ester compound(2) was found to be 306. Results of the ¹H-NMR measurement of the estercompound (2) are shown below.

(Results of ¹H-NMR Measurement of Ester Compound (2))

¹H-NMR (400 MHz, CDCl₃, TMS, ppm) δ: 1.24 (m, 3H), 1.50 (m, 2H), 1.70(m, 5H), 2.09 (m, 2H), 2.55 (m, 2H), 2.65 (m, 1H), 7.25 (d, 1H), 7.46(t, 1H), 7.50 (m, 2H), 7.71 (d, 1H), 7.86 (m, 1H), 7.92 (m, 1H)

(Third Stage: Production of Naphthol Compound (1))

Subsequently, the temperature of the reaction solution obtained in thesecond stage was elevated to 20° C., and a Fries rearrangement reactionwas carried out at that temperature for 2 hours.

A part of the obtained reaction solution was sampled in ice water,thereby separating an oily phase and an aqueous phase from each other.Thereafter, the oily phase was washed with 100 mL of a 2% by mass sodiumhydroxide aqueous solution twice and 100 mL of distilled water twice,followed by dehydration over 10 g of anhydrous sodium sulfate. Theobtained oily phase was analyzed by means of gas chromatography. As aresult, a total purity of the naphthol compound (1) as a Friesrearrangement compound and the ester compound (2) (naphthol compound(1)/ester compound (2)/=72.2/27.8) was found to be 70.9%.

Furthermore, the reaction solution was cooled to a temperature of 0° C.,and this temperature was kept for 8 hours, thereby advancing a Friesrearrangement reaction.

The reaction solution was drawn out from the bottom of the autoclaveinto ice water, thereby separating an oily phase and an aqueous phasefrom each other. Thereafter, the oily phase was washed with 100 mL of a2% by mass sodium hydroxide aqueous solution twice and 100 mL ofdistilled water twice, followed by dehydration over 10 g of anhydroussodium sulfate. The obtained oily phase was analyzed by means of gaschromatography. As a result, there were obtained reaction results inwhich a total purity of the naphthol compound (1) as a Friesrearrangement compound and the ester compound (2) (naphthol compound(1)/ester compound (2)/=81.3/18.7) was 73.8%.

(Distillation)

Simple Distillation:

The obtained solution was subjected to simple distillation. As a result,there was obtained, as a major distillate, 142.1 g (yield: 40.7% basedon DHDCPD) of a product having a total purity of the naphthol compound(1) as a Fries rearrangement compound and the ester compound (2)(naphthol compound (1)/ester compound (2)/=80.8/19.2) of 92.4%.Fluctuation in a Fries rearrangement compound/ester ratio to be causeddue to the distillation was not observed.

Rectifying Distillation:

Furthermore, a desired component was isolated by means of rectificationusing a rectifying column (theoretical number of plates: 20 plates) andanalyzed by means of GC-MS. As a result, a molecular weight of thedesired Fries rearrangement compound was found to be 306. Results of the¹H-NMR measurement of the naphthol compound (1) are shown below.

(Results of ¹H-NMR Measurement of Naphthol Compound (1))

¹H-NMR (400 MHz, CDCl₃, TMS, ppm) δ: 0.91 (m, 1H), 1.21 (m, 4H), 1.30(m, 1H), 1.49 (m, 1H), 1.66 (m, 1H), 1.78 (m, 2H), 2.06 (d, 2H), 2.45(q, 1H), 2.85 (d, 1H), 2.99 (t, 1H), 7.23 (d, 1H), 7.51 (t, 1H), 7.61(t, 1H), 7.74 (d, 1H), 7.93 (d, 1H), 8.48 (d, 1H), 14.53 (s, 1H)

Production Example 1

Production of Polyfunctional Dimethylnaphthalene Formaldehyde Resin

In a bottom-removal four-necked flask having an internal volume of 2liters and equipped with a Dimroth condenser, a thermometer and astirring blade, 218 g of 1,5-dimethylnaphthalene (1.4 moles,manufactured by Mitsubishi Gas Chemical Company, Inc.), 420 g (5.6 molesas formaldehyde) of a 40% by mass formalin aqueous solution(manufactured by Mitsubishi Gas Chemical Company, Inc.) and 194 g of 98%by mass sulfuric acid (manufactured by Kanto Chemical Co., Inc.) werecharged, and the mixture was allowed to react for 7 hours in a nitrogengas stream at atmospheric pressure while refluxing at 100° C. 360 g ofethylbenzene was added as a diluting solvent, and after allowing themixture to stand, an aqueous phase as a lower phase was removed.Furthermore, after neutralization and washing with water, theethylbenzene and unreacted 1,5-dimethylnaphthalene were distilled off invacuo, thereby obtaining 250 g of a 1,5-dimethylnaphthalene formaldehyderesin (hereinafter sometimes referred to as “resin A”) which is a palebrown solid.

As a result of the GPC measurement, the resin had Mn of 550, Mw of 1,130and Mw/Mn of 2.05. The obtained resin was found to have a mean value ofthe number of substituted hydrogen atoms per one naphthalene ring of2.6.

Production Example 2

Production of Monomethylnaphthalene Formaldehyde Resin

In a bottom-removal separable flask having an internal volume of oneliter and equipped with a Dimroth condenser, a thermometer and astirring blade, 142.2 g (1.0 mole) of 1-methylnaphthalene (manufacturedby Wako Pure Chemical Industries, Ltd., content of sulfur atom: 2,200ppm, content of nitrogen atom: 3.9 ppm), 150.0 g (2.0 moles asformaldehyde) of a 40% by mass formalin aqueous solution (manufacturedby Mitsubishi Gas Chemical Company, Inc.) and 51.4 g of 98% by masssulfuric acid (manufactured by Kanto Chemical Co., Inc.) were charged,and the mixture was allowed to react for 5 hours in a nitrogen gasstream at atmospheric pressure while refluxing at 100° C. 160 g ofethylbenzene was added as a diluting solvent, and after allowing themixture to stand, an aqueous phase as a lower phase was removed.Furthermore, after neutralization and washing with water, theethylbenzene and unreacted 1-methylnaphthalene were distilled off invacuo, thereby obtaining 150 g of a 1-methylnaphthalene formaldehyderesin (hereinafter sometimes referred to as “resin B”) which is aviscous liquid at ordinary temperature.

As a result of the GPC measurement, the resin had Mn of 376, Mw of 405and Mw/Mn of 1.08. The obtained resin was measured by means of ¹H-NMR.As a result, the resin was found to have a mean value of the number ofsubstituted hydrogen atoms per one naphthalene ring of 1.4.

Example 2

In a four-necked flask having an internal volume of 0.5 liters andequipped with a Dimroth condenser, a thermometer and a stirring blade,90 g of the resin A obtained in Production Example 1, 71.1 g (0.49moles) of 1-naphthol and 0.36 g of p-toluenesulfonic acid were added ina nitrogen gas stream, the temperature was elevated to 185° C., and themixture was allowed to react for 4 hours. After diluting with a solvent,neutralization and washing with water were carried out, and desolvationand removal of 1-naphthol were carried out in vacuo, thereby obtaining160 g of a pale brown solid.

As a result of the GPC analysis, the solid had Mn of 848, Mw of 1,630and Mw/Mn of 1.93 and also had a hydroxyl group value of 175 mg-KOH/g.Results of the evaluation of heat resistance of the obtained modifiedresin are shown in Table 1.

Example 3

The experiment was carried out in the same manner as in Example 2,except that the charge amount of the 1-naphthol in Example 2 was changedto 38.6 g (0.27 moles), thereby obtaining 130 g of a pale brown solid.

As a result of the GPC analysis, the solid had Mn of 823, Mw of 2,640and Mw/Mn of 3.21 and also had a hydroxyl group value of 96 mg-KOH/g.Results of the evaluation of heat resistance of the obtained modifiedresin are shown in Table 1.

Example 4

The experiment was carried out in the same manner as in Example 2,except that 72.5 g (0.25 moles) of the naphthol compound (1) obtained inExample 1 was used in place of 71.1 g (0.49 moles) of the 1-naphthol inExample 2 and that the addition amount of the p-toluenesulfonic acid waschanged to 0.22 g, thereby obtaining 142 g of a pale brown solid.

As a result of the GPC analysis, the solid had Mn of 688, Mw of 2,304and Mw/Mn of 3.35 and also had a hydroxyl group value of 47 mg-KOH/g.Results of the evaluation of heat resistance of the obtained modifiedresin are shown in Table 1.

Example 5

The experiment was carried out in the same manner as in Example 2,except that 27.5 g (0.1 moles) of the naphthol compound (1) obtained inExample 1 was used in place of 71.1 g (0.49 moles) of the 1-naphthol inExample 2 and that the addition amount of the p-toluenesulfonic acid waschanged to 0.22 g, thereby obtaining 98 g of a pale brown solid.

As a result of the GPC analysis, the solid had Mn of 787, Mw of 4,601and Mw/Mn of 5.85 and also had a hydroxyl group value of 23 mg-KOH/g.Results of the evaluation of heat resistance of the obtained modifiedresin are shown in Table 1.

Example 6

The experiment was carried out in the same manner as in Example 2,except that 13.3 g (0.05 moles) of the naphthol compound (1) obtained inExample 1 was used in place of 71.1 g (0.49 moles) of the 1-naphthol inExample 2 and that the addition amount of the p-toluenesulfonic acid waschanged to 0.22 g, thereby obtaining 88 g of a pale brown solid.

As a result of the GPC analysis, the solid had Mn of 711, Mw of 3,240and Mw/Mn of 4.56 and also had a hydroxyl group value of 14 mg-KOH/g.Results of the evaluation of heat resistance of the obtained modifiedresin are shown in Table 1.

Example 7

The experiment was carried out in the same manner as in Example 2,except that 1-naphthol (36 g, 0.25 moles) and the naphthol compound (1)(36 g, 0.12 moles) obtained in Example 1 were used in place of 71.1 g(0.49 moles) of the 1-naphthol in Example 2 and that the addition amountof the p-toluenesulfonic acid was changed to 0.22 g, thereby obtaining92 g of a pale brown solid.

As a result of the GPC analysis, the solid had Mn of 911, Mw of 8,100and Mw/Mn of 8.9 and also had a hydroxyl group value of 67 mg-KOH/g.Results of the evaluation of heat resistance of the obtained modifiedresin are shown in Table 1.

Comparative Example 1

The experiment was carried out in the same manner as in Example 2,except that 94.1 g (1.0 mole) of phenol was used in place of 71.1 g(0.49 moles) of the 1-naphthol in Example 2, thereby obtaining 130 g ofa pale brown solid.

As a result of the GPC measurement, the solid had Mn of 678, Mw of 1,130and Mw/Mn of 1.66 and also had a hydroxyl group value of 253 mg-KOH/g.Results of the evaluation of heat resistance of the obtained modifiedresin are shown in Table 1.

Comparative Example 2

The experiment was carried out in the same manner as in Example 2,except that 149 g of the resin B obtained in Production Example 2 wasused in place of 90 g of the resin A in Example 2, thereby obtaining 220g of a pale brown solid.

As a result of the GPC analysis, the solid had Mn of 531, Mw of 627 andMw/Mn of 1.18 and also had a hydroxyl group value of 107 mg-KOH/g.Results of the evaluation of heat resistance of the obtained modifiedresin are shown in Table 1.

TABLE 1 Comparative Comparative Example 2 Example 3 Example 4 Example 5Example 6 Example 7 Example 1 Example 2 Naphthalene formaldehyde Resin AResin A Resin A Resin A Resin A Resin A Resin A Resin B resin (g) 90 9090 90 90 90 90 149  Modifying agent 1-Naphthol   71.1   38.6 — — — 36 —  71.1 (g) Naphthol — —   72.5   27.5   13.3 36 — — compound (1) Phenol— — — — — —   94.1 — Heat mass loss rate 19 23 17 20 22 21 33 46 (heatresistance)

It is understood from Table 1 that a modified resin obtained bysubjecting a polyfunctional dimethylnaphthalene formaldehyde resin(resin A) to modification with a naphthol is more excellent in heatresistance than a polyfunctional dimethylnaphthalene formaldehyde resinhaving been subjected to modification with only a phenol.

On the other hand, in a monomethylnaphthalene formaldehyde resin (resin2), even when modification with a naphthol was applied, the thermal massloss was large, and the heat resistance was low.

INDUSTRIAL APPLICATION

The modified dimethylnaphthalene formaldehyde resin of the presentinvention can be utilizing for widespread applications such as anelectrical insulating material, a resin for resist, a semiconductorsealing resin, an adhesive for printed wiring board, a matrix resin forelectrical laminate or prepreg to be mounted in electrical instruments,electronic instruments, industrial instruments, etc., a buildup laminatematerial, a resin for fiber-reinforced plastic, a sealing resin forliquid crystal display panel, a paint, a variety of coating agents, anadhesive and the like.

The invention claimed is:
 1. A modified dimethylnaphthalene formaldehyderesin obtained by a process comprising modifying a polyfunctionaldimethylnaphthalene formaldehyde resin comprising a constituent unitrepresented by formula [1] in a molecule thereof with at least oneselected from the group consisting of a phenol represented by formula[2], a naphthol represented by formula [3] and a naphthol represented byformula [4]:

wherein at least one of the naphthol represented by formula [3] and thenaphthol represented by [4] is included; and R¹ represents an alkylgroup comprising from 1 to 4 carbon atoms; each of R², R³ and R⁴independently represents a hydrogen atom or an alkyl group comprisingfrom 1 to 3 carbon atoms; A is represented by —(OCH₂)_(t)—; t is from 0to 2; x is from 0 to 4; and y represents an integer of from 0 to 2,wherein the polyfunctional dimethylnaphthalene formaldehyde resin isobtained through a condensation reaction between a dimethylnaphthaleneand formaldehyde, a molar ratio of the dimethylnaphthalene toformaldehyde is from 1/2.5 to 1/6, and in the polyfunctionaldimethylnaphthalene formaldehyde resin comprising a constituent unitrepresented by formula [1] in a molecule thereof, a mean value of thenumber of hydrogen atoms substituted by a reaction producing thedimethylnaphthalene formaldehyde resin, among the six hydrogen atomsdirectly bonded on a naphthalene ring, is from 1.5 to 3.5.
 2. Themodified dimethylnaphthalene formaldehyde resin according to claim 1,wherein a dimethylnaphthalene which is a raw material of thepolyfunctional dimethylnaphthalene formaldehyde resin comprising aconstituent unit represented by formula [1] in a molecule thereof, is atleast one member selected from the group consisting of1,5-dimethylnaphthalene, 1,6-dimethylnaphthalene,2,6-dimethylnaphthalene, 1,7-dimethylnaphthalene,1,8-dimethylnaphthalene, and 2,7-dimethylnaphthalene.
 3. The modifieddimethylnaphthalene formaldehyde resin according to claim 2, wherein thedimethylnaphthalene is a dimethylnaphthalene obtained by a chemicalsynthesis, wherein starting raw materials for the chemical synthesiscomprise o-xylene and 1,3-butadiene, or p-xylene and 1,3-butadiene. 4.The modified dimethylnaphthalene formaldehyde resin according to claim1, wherein the phenol represented by formula [2] is at least oneselected from the group consisting of phenol, cresol, 4-t-butylphenol,and xylenol.
 5. The modified dimethylnaphthalene formaldehyde resinaccording to claim 1, wherein the naphthol represented by formula [3] is1-naphthol and/or 2-naphthol.
 6. The modified dimethylnaphthaleneformaldehyde resin according to claim 1, wherein the naphtholrepresented by formula [4] is:


7. The modified dimethylnaphthalene formaldehyde resin according toclaim 1, having a weight average molecular weight (Mw) of from 500 to5,000.